A class, PS class discussion

[ol38y]

I thought I'd open this discussion here on some of the A and PS rules.

Personally I'd like to see some discussion about the 30 deg. total lock for A class entries. Personally I think there is a safety issue here. My ability to control my bike in anything other then an optimal situation is comprimised. If as I was told at El Mirage " that's all the steering you need", then why not limit the steering on cars as well?    Thoughts anyone. Todd, Willie, JN

Willie, fenders are allowed because they are not dissalowed as I read it.

Larry 

[Seldom Seen Slim]

Okay, Larry -- I'll bite.  Are you saying you don't like the 30-degree rule because it allows too little or too much steering control?  You don't specify.  I sure don't have any reason to say it's too little, as I've never had to use anything near that much while on the course/going to the return road.  I haven't measured how much lock-yo-lock I've got set on my nitrous bike, but it's around that 30 degrees, I'd say (it's set with adjustable stops -- very little turning is allowed).  If you're saying that we could do okay with less -- well, my experience says yes, that'd be okay -- as long as I've got about 20 acres to turn around in on the way from pit to the trailer.

[narider]

Hi Larry,
Although I don't agree with the 30* rule either, I believe at least some of the cars are limited to that or less as well (whether by rule or not, I'm not sure).
If you do a search for "Jack Dolan on rules" you'll get to one of the most viewed threads on here. Look a few pages into (about half way through?) that thread (to the 2007? season I believe) and you'll find a series of posts leading into 2008 starting to discuss the rule in question. Check it out if you haven't, and then posts your additional thoughts here... I think their might be some reservation by some in having that particular thread resurected ( lol - personally I think it would be of benefit, as would having Jack back - pay attention to his thoughts on it... very valuable imo). At anyrate, the rule in question is a serious safety hazard at Maxton, but I have yet to get experience the salt under my wheels with alot of these rules in mind (another reason I just can't wait until the end of the week to get out of here - and I NEVER want to get out of here by the way). I'm sure there's some of my thoughts on it in that thread, but I'm looking forward to the thoughts of those of you that are already abiding by the rule and especially the ones that have been on the salt long before it was an issue at a meeting and became a rule.

On the fender v. partial streamlining... well the fender is it's own entity with it's own purpose. The aero advantage is decided with regards to the item in question and what it's "sole" or "most prominent" purpose is. A gas tank of any size (legal in it's frame class of course) is permitted as it's purpose is as a gas tank, but not if it goes beyond the normal limitations of a gas tank and wraps around the steering head to create a fairing in a non-streamlined class. A fender is considered the same, as it's purpose is to protect the bike and rider from debri slung off the front tire, but it would not be if it created a fairing by extending 2 foot above the tire and a foot to each side of the bike while being extended fully to the ground. That is why the fender has it's maximum legal dimensions in relation to the front tire, the forks and it's circumfrance listed in the book.
Does that make sense?
Todd

[ol38y]

Slim, I say it allows too little. I fail to see the need to regulate the steering lock. I've heard it said that it is supposed to eliminate "tank slappers". I dissagree. I see that it only limits to control my bike in the event of a tank slapper. The way I see it, if you go into a "TS" and the steering runs into the stop before it is allowed to unload it will transfer that energy down the bike and probably make it worse. I hope I explained that well. I agree that in a normal run a person would probably not use much more then 30 deg. I'm saying that in an abnormal run when a person is trying to regain control I want all the steering lock I can get. If for whatever reason I felt the only way out was to lay the bike down I don't think it could be done with only 30 deg lock. So, no, I don't like the rule. I was just curious if I was alone.

[ol38y]

Todd, I remember the topic as well. I read that one with great interest. Then, as you say, my observation as well, it just went away. I will go back and look it up to reread it. That is kinda why I brought it up again. I felt it needs more discussion. I still think it a safety issue anywhere. Probably more so at Maxton or Texas. My biggest problem with it is it takes away my ability to control my bike in adverse conditions. To be told that that's all you need is not a good answer IMHO.

Larry

[narider]

You are not alone Larry and you stated your reasoning perfectly imo.
Todd

[Nortonist 592]

My bike has had 30 deg. (give or take a degree) for years now.  I don't have a problem with it.  If the bike is going to go into a tank slapper I would want the slap to be a restricted as possible.  With the swing restricted to 15 deg each way you hae a better chance of controlling it than if the swing is, say, forty deg. each way.  Less chance to build inertia etc.  My only whine about that rule is when I move the bike around the garage.  Turning off at El Mirage could be done quite easily with five deg. of lock.

[ol38y]

I'll do this tomorrow, but anyone else feel free to chime in. 

Larry

[Dean Los Angeles]

Based on Larry's picture I'd say he is used to 180 degrees of lock on a regular basis.

Steering lock has nothing to do with tank slappers. It's about geometry. If you have any frame flex it changes the relation between the front and rear wheels. It can be induced by the throttle or suspension. Or just not having the wheels aligned. Once a wobble starts the rider can turn it into a tank slapper by stiffening up and over correcting. Steering dampers are required because they slow down the reaction time of the forks. Or is it the rider? Limiting lock isn't going to change the picture.

[narider]

Based on Larry's picture I'd say he is used to 180 degrees of lock on a regular basis.

Steering lock has nothing to do with tank slappers. It's about geometry. If you have any frame flex it changes the relation between the front and rear wheels. It can be induced by the throttle or suspension. Or just not having the wheels aligned. Once a wobble starts the rider can turn it into a tank slapper by stiffening up and over correcting. Steering dampers are required because they slow down the reaction time of the forks. Or is it the rider? Limiting lock isn't going to change the picture.

Well put Dean (that's a paragraph for the book imo).
I think it's the rider and not the bike that the damper helps the most in an emergency situation (IE: many riders can turn a simple high speed wobble into a tank slapper by chopping the throttle, etc. if there's not a damper to slow their reactions down).
Todd

[ol38y]

Very well said Dean. If you have an ill handling bike, lessening the steering lock will not fix the problem. IMO it will only exacerbate the problem since the energy will be redirected back to the frame. You'll then find out if you have any flex in your frame or swingarm...

Larry

[racer x]

Since we are on the subject of tank slappers . I have made adjustments to my bike to make it faster. It is the new 250 ninja . It has a 26 deg steering angle and I have lowered the rear so it is slacker still. My concern is everything else I have done.Like changing the rear sets to move my body mass down and back and removing the headlight and replacing the front body with light weight fiberglass has moved my center of gravity back. My Question is .As I go faster with more power am I headed for a tank slapper ?And What should I do if it starts?
I want to fit a dampner but it is not required till 125 mph . The bike is rock solid at speed and can be handled with one hand .         thanks  Eric

[Nortonist 592]

"Am I headed for a tank slapper?"    Not necessarily.  If its handling good theres no reason to believe it will go to hell when you get to the salt.  If you have any doubts put on a steering damper.  This tank slapper thing is getting ridiculous.

[Seldom Seen Slim]

Eric, a couple of years ago our nitrous bike HAD handled fine at speed for the first few runs. But then we farkeld the rear shock and set the compression rebound too slow, so the back end would get lower and lower 'til the shock was bottomed (this would happen in the first mile or two of a run).  When the rear was all the way down -- it's time for a wiggly front end, folks, and the only way out was to crank on more throttle to lift the front end.

Both of us had it happen (wouldn't happen 'til we were at about a buck-sixty), and it wasn't until we readjuysted the back shock that the slapping stopped.  I'd be wary about lowering the back end of the bike like you say you've done -- that changes the gteometry of the front suspension and might not give good results.

I'm reporting how we had the issue -- we hope it won't be one with you.  We look forward to seeing you -- and everyone -- out here Sunday.

[racer x]

Thank you Jon for th warning. I will move slowly with adjustments.
I would do anything to be there next week 
This will be the last speed week I miss. Even if I just ride out and sleep on the ground I will make it. Ride safe . Everyone